North Korean defectors may have been exposed to radiation

SEOUL (Reuters) - At least four defectors from North Korea have shown signs of radiation exposure, the South Korean government said on Wednesday, although researchers could not confirm if they were was related to Pyongyang's nuclear weapons program.

The four are among 30 former residents of Kilju county, an area in North Korea that includes the nuclear test site Punggye-ri, who have been examined by the South Korean government since October, a month after the North conducted its sixth and most powerful nuclear test, Unification Ministry spokesman Baik Tae-hyun told a news briefing.

They were exposed to radiation between May 2009 and January 2013, and all defected to the South before the most recent test, a researcher at the Korea Atomic Energy Research Institute, which carried out the examinations, told reporters.

RELATED: Every North Korean missile launch in 2017

16PHOTOS

Every missile launch conducted by North Korea in 2017

See Gallery

Every missile launch conducted by North Korea in 2017

This photo taken on February 12, 2017 and released on February 13 by North Korea's official Korean Central News Agency (KCNA) shows the launch of a surface-to-surface medium long-range ballistic missile Pukguksong-2 at an undisclosed location.
North Korea said on February 13 it had successfully tested a new ballistic missile, triggering a US-led call for an urgent UN Security Council meeting after a launch seen as a challenge to President Donald Trump. / AFP PHOTO / KCNA via KNS / STR / South Korea OUT / REPUBLIC OF KOREA OUT ---EDITORS NOTE--- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT 'AFP PHOTO/KCNA VIA KNS' - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS / THIS PICTURE WAS MADE AVAILABLE BY A THIRD PARTY. AFP CAN NOT INDEPENDENTLY VERIFY THE AUTHENTICITY, LOCATION, DATE AND CONTENT OF THIS IMAGE. THIS PHOTO IS DISTRIBUTED EXACTLY AS RECEIVED BY AFP.
/ (Photo credit should read STR/AFP/Getty Images)

TOPSHOT - This undated picture released by North Korea's Korean Central News Agency (KCNA) via KNS on March 7, 2017 shows the launch of four ballistic missiles by the Korean People's Army (KPA) during a military drill at an undisclosed location in North Korea.
Nuclear-armed North Korea launched four ballistic missiles on March 6 in another challenge to President Donald Trump, with three landing provocatively close to America's ally Japan. / AFP PHOTO / KCNA VIA KNS / STR / South Korea OUT / REPUBLIC OF KOREA OUT ---EDITORS NOTE--- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT 'AFP PHOTO/KCNA VIA KNS' - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS
THIS PICTURE WAS MADE AVAILABLE BY A THIRD PARTY. AFP CAN NOT INDEPENDENTLY VERIFY THE AUTHENTICITY, LOCATION, DATE AND CONTENT OF THIS IMAGE. THIS PHOTO IS DISTRIBUTED EXACTLY AS RECEIVED BY AFP. / (Photo credit should read STR/AFP/Getty Images)

TOPSHOT - A man walks past a television screen showing file footage of a North Korean missile launch, at a railway station in Seoul on March 22, 2017.
A new North Korean missile test failed on March 22, the South and US said, two weeks after Pyongyang launched four rockets in what it called a drill for an attack on American bases in Japan. / AFP PHOTO / JUNG Yeon-Je (Photo credit should read JUNG YEON-JE/AFP/Getty Images)

A man walks past a television screen showing file footage of a North Korean missile launch, at a railway station in Seoul on April 5, 2017.
Nuclear-armed North Korea fired a ballistic missile into the Sea of Japan on April 5, just ahead of a highly-anticipated China-US summit at which Pyongyangs accelerating atomic weapons programme is set to top the agenda. / AFP PHOTO / JUNG Yeon-Je (Photo credit should read JUNG YEON-JE/AFP/Getty Images)

A North Korean navy truck carries the 'Pukkuksong' submarine-launched ballistic missile (SLBM) during a military parade marking the 105th birth anniversary of country's founding father, Kim Il Sung in Pyongyang, April 15, 2017. North Korea has escalated tests of its SLBM programme in the last year. Whilst the isolated country is not yet believed to have an operational submarine capable of carrying more than one missile at the time, its enemies are worried that a fully-functional SLBM would make tracking and intercepting a North Korean missile launch and the submarine from which it was fired very difficult. REUTERS/Damir Sagolj TPX IMAGES OF THE DAY SEARCH "PARADE WID" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

This picture taken on May 14, 2017 and released from North Korea's official Korean Central News Agency (KCNA) on May 15 shows a test launch of the ground-to-ground medium long-range strategic ballistic rocket Hwasong-12 at an undisclosed location. / AFP PHOTO / KCNA VIA KNS / STR / South Korea OUT / REPUBLIC OF KOREA OUT ---EDITORS NOTE--- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT 'AFP PHOTO/KCNA VIA KNS' - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS
THIS PICTURE WAS MADE AVAILABLE BY A THIRD PARTY. AFP CAN NOT INDEPENDENTLY VERIFY THE AUTHENTICITY, LOCATION, DATE AND CONTENT OF THIS IMAGE. THIS PHOTO IS DISTRIBUTED EXACTLY AS RECEIVED BY AFP. / (Photo credit should read STR/AFP/Getty Images)

FILE PHOTO - The scene of the intermediate-range ballistic missile Pukguksong-2's launch test in this undated photo released by North Korea's Korean Central News Agency (KCNA) May 22, 2017. KCNA/via REUTERS/File photo ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. EDITORIAL USE ONLY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THIS IMAGE. NO THIRD PARTY SALES. SOUTH KOREA OUT.

People watch a television broadcasting a news report on North Korea firing what appeared to be a short-range ballistic missile, at a railway station in Seoul, South Korea, May 29, 2017. REUTERS/Kim Hong-Ji TPX IMAGES OF THE DAY

SEOUL, SOUTH KOREA - JUNE 08: People watch a television broadcast reporting the North Korean missile launch at the Seoul Railway Station on June 8, 2017 in Seoul, South Korea. According to the South Korean military, North Korea launched several cruise missiles from the east coast toward the ocean on June 8, 2017 in its fourth missile test in four weeks. The launch came amid the international tension surrounding the policy on North Korea, as a day before the newly elected South Korean president, Moon Jae-in, announced the suspension of the deployment of an controversial American missile defence system, and less than a week before the United Nations Security Council expanded the sanctions against North Korea. (Photo by Chung Sung-Jun/Getty Images)

This picture taken and released on July 4, 2017 by North Korea's official Korean Central News Agency (KCNA) shows the test-fire of the intercontinental ballistic missile Hwasong-14 at an undisclosed location.
North Korea declared on July 4 it had successfully tested its first intercontinental ballistic missile -- a watershed moment in its push to develop a nuclear weapon capable of hitting the mainland United States. / AFP PHOTO / KCNA VIA KNS / STR / South Korea OUT / REPUBLIC OF KOREA OUT ---EDITORS NOTE--- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT 'AFP PHOTO/KCNA VIA KNS' - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS
THIS PICTURE WAS MADE AVAILABLE BY A THIRD PARTY. AFP CAN NOT INDEPENDENTLY VERIFY THE AUTHENTICITY, LOCATION, DATE AND CONTENT OF THIS IMAGE. THIS PHOTO IS DISTRIBUTED EXACTLY AS RECEIVED BY AFP.
/ (Photo credit should read STR/AFP/Getty Images)

A photo taken on July 6, 2017 shows a mass dance event as part of celebrations marking the July 4 launch of the Hwasong-14 intercontinental ballistic missile, in Pyongyang.
Fireworks lit up the sky over Pyongyang's Juche Tower as North Korea celebrated its launch of intercontinental ballistic missile, a milestone in its decades-long weapons drive. On July 4 -- the United States' Independence Day -- it launched a Hwasong-14 rocket that analysts and overseas officials said had a range of up to 8,000 kilometres, which would put Alaska and Hawaii within reach. / AFP PHOTO / KIM Won-Jin (Photo credit should read KIM WON-JIN/AFP/Getty Images)

TOPSHOT - This July 28, 2017 picture released from North Korea's official Korean Central News Agency (KCNA) on July 29, 2017 shows North Korea's intercontinental ballistic missile (ICBM), Hwasong-14 being lauched at an undisclosed place in North Korea.
Kim Jong-Un boasted of North Korea's ability to strike any target in the US after a second ICBM test that weapons experts said could even bring New York into range - in a potent challenge to US President Donald Trump. / AFP PHOTO / KCNA VIS KNS / STR / South Korea OUT / REPUBLIC OF KOREA OUT ---EDITORS NOTE--- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT 'AFP PHOTO/KCNA VIA KNS' - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS
THIS PICTURE WAS MADE AVAILABLE BY A THIRD PARTY. AFP CAN NOT INDEPENDENTLY VERIFY THE AUTHENTICITY, LOCATION, DATE AND CONTENT OF THIS IMAGE. THIS PHOTO IS DISTRIBUTED EXACTLY AS RECEIVED BY AFP.
TO GO WITH NKorea-nucelar-missile-Japan-SKorea-politics, FOCUS by Shingo Ito and Park Chan-Kyong / (Photo credit should read STR/AFP/Getty Images)

SEOUL, SOUTH KOREA - AUGUST 26: People watch a television broadcast reporting the North Korean missile launch at the Seoul Railway Station on August 26, 2017 in Seoul, South Korea. North Korea launched several ballistic missiles into the East Sea resuming a provocative act in a month despite Washington's diplomacy-first approach toward the belligerent regime. (Photo by Chung Sung-Jun/Getty Images)

TOPSHOT - This picture from North Korea's official Korean Central News Agency (KCNA) taken on August 29, 2017 and released on August 30, 2017 shows North Korea's intermediate-range strategic ballistic rocket Hwasong-12 lifting off from the launching pad at an undisclosed location near Pyongyang.
Nuclear-armed North Korea said on August 30 that it had fired a missile over Japan the previous day, the first time it has ever acknowledged doing so. / AFP PHOTO / KCNA VIA KNS / STR / South Korea OUT / REPUBLIC OF KOREA OUT ---EDITORS NOTE--- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT 'AFP PHOTO/KCNA VIA KNS' - NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS
THIS PICTURE WAS MADE AVAILABLE BY A THIRD PARTY. AFP CAN NOT INDEPENDENTLY VERIFY THE AUTHENTICITY, LOCATION, DATE AND CONTENT OF THIS IMAGE. THIS PHOTO IS DISTRIBUTED EXACTLY AS RECEIVED BY AFP. / The erroneous mention[s] appearing in the metadata of this photo by STR has been modified in AFP systems in the following manner: [at an undisclosed location near Pyongyang] instead of [in Pyongyang]. Please immediately remove the erroneous mention[s] from all your online services and delete it (them) from your servers. If you have been authorized by AFP to distribute it (them) to third parties, please ensure that the same actions are carried out by them. Failure to promptly comply with these instructions will entail liability on your part for any continued or post notification usage. Therefore we thank you very much for all your attention and prompt action. We are sorry for the inconvenience this notification may cause and remain at your disposal for any further information you may require. (Photo credit should read STR/AFP/Getty Images)

SEOUL, SOUTH KOREA - SEPTEMBER 15: People watch a television broadcast reporting the North Korean missile launch at the Seoul Railway Station on September 15, 2017 in Seoul, South Korea. North Korea launched a ballistic missile over Japan just days after the U.N. Security Council adopted new sanctions against the regime over its sixth nuclear test on Sept. 3. (Photo by Chung Sung-Jun/Getty Images)

People watch a television screen showing a file video footage of North Korea's missile launch, at a railway station in Seoul on November 29, 2017.
North Korea test fired what appeared to be an intercontinental ballistic missile on November 29, in a major challenge to US President Donald Trump after he slapped fresh sanctions on Pyongyang and declared it a state sponsor of terrorism. / AFP PHOTO / JUNG Yeon-Je (Photo credit should read JUNG YEON-JE/AFP/Getty Images)

Up Next

See Gallery

Discover More Like This

HIDE CAPTION

SHOW CAPTION

of

SEE ALL

BACK TO SLIDE

North Korea has conducted six nuclear bomb tests since 2006, all in tunnels deep beneath the mountains of Punggye-ri, in defiance of U.N. Security Council resolutions and international condemnation.

The researcher cautioned that there were a number of ways people may be exposed to radiation, and that none of the defectors who lived had lived in Punggye-ri itself showed specific symptoms.

A series of small earthquakes in the wake of the last test - which the North claimed to be of a hydrogen bomb - prompted suspicions that it may have damaged the mountainous location in the northwest tip of the country.

Experts warned that further tests in the area could risk radioactive pollution.

After the Sept. 3 nuclear test, China’s Nuclear Safety Administration said it had begun emergency monitoring for radiation along its border with North Korea.

And in early December, a state-run newspaper in China’s Jilin province, which borders North Korea and Russia, published a page of “common sense” advice on how readers can protect themselves from a nuclear weapons attack or explosion.

Cartoon illustrations of ways to dispel radioactive contamination were also provided, such as using water to wash off shoes and using cotton buds to clean ears, as well as a picture of a vomiting child to show how medical help can be sought to speed the expulsion of radiation through stomach pumping and induced urination.

RELATED: Key moments between North Korea and the US

34PHOTOS

Key moments in 2017 between US and North Korea

See Gallery

Key moments in 2017 between US and North Korea

NEW YEARS DAY MISSILE LAUNCH

On January 1, 2017, North Korea's leader Kim Jong Un warned that an intercontinental ballistic missile (ICBM) was in the 'final stages' of development.

During a visit to North Korea's border on March 17, Secretary of State Rex Tillerson was unwittingly photographed by a North Korean soldier, who can be seen peering into the room on the right side of the image.

President Trump called North Korean dictator Kim Jong Un 'a pretty smart cookie' in an interview that went viral on April 30.

'At a very young age, he was able to assume power. A lot of people, I'm sure, tried to take that power away, whether it was his uncle or anybody else. And he was able to do it. So obviously, he's a pretty smart cookie,' Trump told CBS News.

The president also said he'd be 'honored' to meet with the North Korean leader.

KIM JONG UN'S LETTER TO CONGRESS

In early May, North Korea said it would continue its nuclear weapons tests and boost force 'to the maximum' in a stark warning to the U.S.

U.N. Ambassador Nikki Haley said North Korea's actions were 'quickly closing off the possibility of a diplomatic solution' and that the United States was prepared to use force 'if we must.'

'PILE OF ASH'

In a bold statement, North Korea threatened to turn the U.S. into a 'pile of ash' on July 12.

US THREATENED WITH 'MERCILESS BLOW'

On July 27, a North Korean spokesperson said, 'Should the U.S. dare to show even the slightest sign of attempt to remove our supreme leadership, we will strike a merciless blow at the heart of the U.S. with our powerful nuclear hammer, honed and hardened over time.'